Antibacterial poly (ethylene glycol) diacrylate/chitosan hydrogels enhance mechanical adhesiveness and promote skin regeneration

Eco-friendly synthesis of functionalized chitosan-based nanoantibiotic system for potential delivery of linezolid as antimicrobial agents

To obtain a healthy human being with beneficial microflora against different pathogenic infections, classical antibiotics with nanosized biomaterials were used to inhibit the growth of bacterium by their potent synergistic effect. Hence, this study planned to load an oxazolidinone antibiotic named linezolid (LD) onto functionalized chitosan (CN) with 3, 5- dinitrosalyslic acid (DA) via microwave synthesis without harsh condition. The exploring synergistic effect of linezolid (LD) with CN/DA controllable nanostructure was compact efflux-mediated methicillin-resistant Staphylococcus aureus (MRSA) burden and other selected bactericide Gram-positive ((S. aureus), Gram-negative (E. coli), Fungi (C. albicans), Yeast (A. niger), and E. faecalis. The obtained results showed that LD was incorporated into both the internal and external surface of the aggregated CN/DA nanosystem with an average diameter of 150 nm ± 4 hints of the drug loading. Owing to the nature of functionalized CN, the release efficiency attains 98.4% within 100 min. The designed LD@CN/DA exhibited inhibition zone 54 mm, 59 mm, 69 mm, 54 mm, 57 mm, and 24 mm against the tested microbes respectively rather than individual LD. The major target of the current research is achieved by using LD@CN/DA as a nanoantibiotic system that has exceptional consistently active against multi-resistant pathogens, in between MRSA which resist LD. Also, cell viability was performed even after three days of direct cell culture on the surface of the designed nanoantibiotic. The mechanism of microbial inhibition was correlated and rationalized to different charges and the presence of oxygen species against microbial infections. Our findings provide a deep explanation about nanostructured antibiotics design with enhanced potentially pathogen-specific activity.

Tannic acid-reinforced methacrylated chitosan/methacrylated silk fibroin hydrogels with multifunctionality for accelerating wound healing

Natural polymeric hydrogel featuring multifunctional properties is more attractive as wound dressing. Herein, Tannic acid (TA)-reinforced methacrylated chitosan (CSMA)/methacrylated silk fibroin (SFMA) hydrogels were fabricated by two-step method of photopolymerization and TA solution incubating treatment. The TA in hydrogels not only served as second crosslinker improving the mechanical performance of up to a 5-fold increase (5 % TA treatment) than the pristine one, but also as functional molecule that endowed the hydrogels with enhanced adhesiveness and antioxidative properties. Besides, the introduction of TA into hydrogels further improved the antimicrobial activities against both Escherichia coli (E. coli) and Staphylococcus Aureus (S. aureus), as well as the cytocompatibility on fibroblasts. Moreover, it was demonstrated that the TA-treated CSMA/SFMA hydrogels could significantly promote wound healing in a full-thickness skin defect model. Collectively, these results showed that TA-reinforced CSMA/SFMA hydrogels could be a promising candidate as wound dressing.

A Novel Composite Hydrogel Composed of Formic Acid-Decellularized Pepsin-Soluble Extracellular Matrix Hydrogel and Sacchachitin Hydrogel as Wound Dressing to Synergistically Accelerate Diabetic Wound Healing

Extracellular matrix (ECM) hydrogel can create a favorable regenerative microenvironment and act as a promising dressing for accelerating the healing of diabetic wound. In this study, a simple and effective decellularization technique was developed and optimized to obtain acellular extracellular matrix (aECM) from porcine skin. It was found that decellularization at 30% formic acid for 72 h effectively decellularized porcine skin while retaining >75% collagen and ~37% GAG in the aECM with no presence of nuclei of cellular remnants. aECM hydrogel was fabricated by digesting aECM with pepsin in various acidic solutions (0.1 N HCl, glycolic acid (GA) and 2-pyrrolidone-5-carboxylic acid (PCA)) and then treated with a pH-controlled neutralization and temperature-controlled gelation procedure. Based on physical characterizations, including SDS-PAGE, rheological analysis and SEM analysis, aECM_HCl hydrogels fabricated at 25 mg/mL in 0.1 N HCl were selected. Four polymeric ECM-mimic hydrogels, including sacchachitin (SC), hyaluronic acid (HA) and chitosan (CS) and three composite hydrogels of combining SC either with aECM_HCl,25 (aECM_HCl/SC), HA (HA/SC) or CS (SC/CS) were prepared and evaluated for WS-1 cell viability and wound-healing effectiveness. Cell viability study confirmed that no hydrogel dressings possessed any toxicity at all concentrations examined and ECM_HCl, HA and ECM_HCl/SC at higher concentrations (>0.05%) induced statistically significant proliferation. Diabetic wound healing study and histological examinations revealed that ECM_HCl/SC hydrogel was observed to synergistically accelerate wound healing and ultimately stimulated the growth of hair follicles and sweat glands in the healing wound indicating the wound had healed as functional tissues. The results support the great potential of this newly produced ECM_HCl/SC composite hydrogel for healing and regeneration of diabetic wounds.

Hydrogels as Potential Nano-, Micro- and Macro-Scale Systems for Controlled Drug Delivery

This review is an extensive evaluation and essential analysis of the design and formation of hydrogels (HGs) for drug delivery. We review the fundamental principles of HGs (their chemical structures, physicochemical properties, synthesis routes, different types, etc.) that influence their biological properties and medical and pharmaceutical applications. Strategies for fabricating HGs with different diameters (macro, micro, and nano) are also presented. The size of biocompatible HG materials determines their potential uses in medicine as drug carriers. Additionally, novel drug delivery methods for enhancing treatment are discussed. A critical review is performed based on the latest literature reports.

Effect of matrix stiffness and adhesion ligand density on chondrogenic differentiation of mesenchymal stem cells

Adhesion ligands and mechanical properties of extracellular matrix (ECM) play significant roles in directing mesenchymal stem cells' (MSCs) behaviors, but how they affect chondrogenic differentiation of MSCs has rarely been studied. In this study, we investigated the effects of matrix stiffness and adhesion ligand density on proliferation and chondrogenic differentiation of MSCs by using UV crosslinked hydrogels comprised of methacrylated gelatin (GelMA) and poly(ethylene glycol) diacrylate (PEGDA) of different weight ratios. The PEGDA/GelMA hydrogels were fabricated by adjusting the weight ratio of PEGDA and GelMA with low or high adhesion ligand density (0.05 and 0.5% GelMA, respectively) and independent tunable stiffness (1.6, 6, and 25 kPa separately for hydrogels with 5, 10, and 15% PEGDA). MSCs presented differential behaviors to ECM by adjusting its adhesion ligand density and stiffness. Cell proliferation and chondrogenic differentiation could be enhanced with the improvement of adhesive properties and stiffness, evidenced by cell viability assay, hematoxylin-eosin staining, Safranin O staining, immunohistochemistry (Collagen types II, Col2a1), as well as the chondrogenic genes expression of Col2a1, Acan, and Sox9. This study may provide new strategies to design the scaffolds for cartilage tissue engineering.